Compacted regenerated cellulose sponges and method of preparing the same

ABSTRACT

Stacks of individual thinly sliced sheets of regenerated cellulose may be compressed at pressures of 2,000-20,000 pounds per square inch to reduce the thickness thereof to 8-20 percent of the original stacked height to obtain a product which remains compressed and in which the individual thin sheets of regenerated cellulose adhere to each other so long as they are dry. The compressed sheets can be cut into desired shapes, packed in shipping boxes, transported and handled on automatic filling machines without falling apart. The individual units are useful in preparing cosmetic pads for cleaning, disinfecting and otherwise applying liquid medicaments to the skin.

llnited States Patent [72] lnventors LeonardJ. Viola [54] COMPACTEDREGENERATED CELLULOSE SPONGES AND METHOD OF PREPARING THE SAME 6 Claims,6 Drawing Figs.

[52] U.S.Cl 161/159, 156/306, 161/269 [51] Int. Cl B32b 3/26, C09 5/00[50] Field ofSearch 161/159,

[56] References Cited UNITED STATES PATENTS 2,133,805 10/1938 Brown161/159 2,744,292 5/1956 Schlosser et al. 161/269 PrimaryExaminer--William .1. Van Balen Attorneys-Harvey W. Edelblute and GeorgeW. Rauchfuss,

ABSTRACT: Stacks of individual thinly sliced sheets of regeneratedcellulose may be compressed at pressures of 2,00020,000 pounds persquare inch to reduce the thickness thereof to 8-20 percent of theoriginal stacked height to obtain a product which remains compressed andin which the individual thin sheets of regenerated cellulose adhere toeach other so long as they are dry. The compressed sheets can be cutinto desired shapes, packed in shipping boxes, transported and handledon automatic filling machines without falling apart. The individualunits are useful in preparing cosmetic pads for cleaning, disinfectingand otherwise applying liquid medicaments to the skin.

PATENIEDJAHI I 1972v 3534 1 3 HEIGHT IN mcucs '6 8 8 8 5' y- PRESSUREEUGENE ll. 6 I3 7 KTTORNEY COMPACTED REGENERATED CELLULOSE SPONCES ANDMETHOD OF PREPARING THE SAME This invention relates to a new and usefularticle of manufacture. More particularly, the invention relates to amultiplicity of individual thin sheets of dry, regenerated cellulosepressed together in compact units which are better adapted for handling,shipping and packaging by automatic machinery.

I-leretofore, medicated or cosmetic cleansing solutions have beenapplied to the skin with cotton pads and similar devices. Cotton padshave the disadvantage that they are not rigid, and do not retain theirshape, and tend to roll up with use and leave a lint residue on theskin. Also, they are not as effective cleansing agents as the sponges tobe described hereinafter since they do not hold as much liquid, do nothave the same effective and desirable scrubbing action, and do not holdas much dirt and skin oil as do the products of the present invention.

The new articles of manufacture of the present invention areparticularly useful in manufacturing cosmetic aids for applyingcleaning, disinfecting, astringent, deodorant and other liquidpreparations to the skin. The eventual product for which the newarticles of the present invention are used comprises a liquidtightpackage containing a plurality of thin wafers of regenerated cellulose,saturated with a solution having a cleaning or other desired cosmeticproperties as indicated above. Such a package might, for instance,contain up to 50 individual sponges of regenerated cellulose of l to 4square inches in area, and from about one sixty-fourth to onefourth inchin thickness. The individual sponges are used by simply opening thecontainer and removing one of the liquid saturated layers from thecontainer, rescaling the package to prevent evaporation of the liquid,and rubbing the wet sponge on the skin.

It has been found that it is difficult to handle dry thinly cut spongesof regenerated cellulose in ordinary manufacturing processes. The thinsponges are very bulky and occupy an unnecessarily large amount of spaceafter they are cut and when they are to be shipped to the place wherethey are to be used in manufacturing cosmetic aids. They are,individually, extremely light in weight and will not stack easily andwill not remain stacked when assembled. A very slight movement, such asa gust of air, may blow them about and they have to handled verycarefully so that a predetermined number of sponges may be placed ineach container. They do not lend themselves to handling with automaticfilling machines. The present invention provides a method of preparingsponges in a unitary form which can be placed in shipping containers ofrelatively small size, which can be shipped economically and filled withautomatic equipment into containers such as jars on an assembly linewhere the finished cosmetic product is made.

In accordance with the present invention a block of regeneratedcellulose sponge material, for example a 20-inch cube, is sliced intothin sections one sixty-fourth inch to onefourth inch thick and theseslices are stacked into a pile. The number of thin sheets in each pileis dependent upon the number of sponges that is desired per package ofproduct, for instance, to 50 individual slices. The dry stacked spongesare then compressed with a hydraulic press. In a preferred example, 36thin sheets of cellulose sponge having an individual nonnal drythickness of 0.060 inches were stacked to provide a pile 2% inches high.When this pile was placed in a hydraulic press and pressure applied, itwas found that at a total pressure of 7,000 pounds per square inch theheight of the pile of square sponges had been reduced to about 0.160inches.

FIG. 1 of the accompanying drawings is a graph showing the compressionof such a pile of sliced sponges as the pressure is increased.

The present invention is based upon the surprising discovery that whenthinly sliced cellulose sponges as described herein are stronglycompressed, they are compacted and adhere together as a unitary mass.The resulting relatively dense, coherent slab can be sawed with a bandsaw, or other appropriate cutting device, into square or other shapes ofdesired size and each resulting unit remains compressed as a coherentunitary mass with the individual sponges sticking together so that theycan be packed in a relatively small container, shipped to a factory andplaced with automatic equip ment into glass jars on a production line.

FIG. 2 of the drawing is a perspective view of an individual thinlysliced sponge of the present invention 10 as it would normally appearwithout having been compressed.

FIG. 3 of the drawing is an elevational view illustrating a stack ofuncompressed cellulose sponges 11 between the platens, 12 and 13, of ahydraulic press.

FIG. 4 of the drawing is an elevational view showing the compressedsponges after pressure is applied.

FIG. 5 of the drawing is an elevational view of a unit of compressedsponges, l4, placed in a jar, 15. A lower section of the jar is cut awayto show the compressed sponges in the jar.

FIG. 6 is an elevation of the same jar of FIG. 5 with the top portioncut away showing the expanded sponges after being saturated withantiseptic cleaning liquid.

As will be apparent, the sponges may be cut into squares, rectangles,circles, ovals or other desirable shapes. Obviously, when the materialis cut in squares there is less waste of cellulose material. In FIG. 2,the corners of the sponge are shown to have been rounded slightly sothat a circular jar will hold larger sponges.

The compressed sponge wafers adhere surprisingly well to each other. Inthe following table there is shown the force that is required toseparate individual sponges from a compressed block of 38 of the same.The individual dry sponges were 1% inches by 1% inches by 1/16 inchbefore being compressed with the total pressure in pounds per squareinch as shown in the following table.

As will be seen, when the dry sponges were compressed with a totalpressure of 8,000 pounds, it took 200 grams of force to separate one ofthe sponges of the compressed group from the others. At 20,000 poundstotal pressure a weight of 370 grams was required to separate thesponges. Accordingly, a plurality of dry sponges sliced to a thicknessof one sixty-fourth of an inch may be pressed together at pressures ofabout 2,000 pounds per square inch to 20,000 pounds per square inch toobtained compressed units which may be handled with ordinary care inpackaging and filling operations without danger of having the spongesfall apart and thus made unsatisfactory for automatic fillingoperations.

It is surprising that the thinly sliced dried sponges remain compressedand adhere to each other when subjected to the pressing operation justdescribed. Thinly sliced sponges of other material, polyurethane foamsponges for example, immediately return to their original thickness whena pile of them is compressed and the pressure released. Furthermore,they dont stick together. On the other hand, the thinly sliced spongesof regenerated cellulose of the present invention remain compacted andstick together. This is probably due to the relatively low degree ofresiliency of the cellulose sponge material and the fact that, when thesponge is cut, the surface is rough due to the ragged edges of the poresand protruding fibers which are a part of the sponge composition. Theseragged edges and protruding fibers tend to intertwine and hold thesponge slices together. However, when an aqueous antiseptic cleaningsolution is added to the compressed sponges they immediately absorb theliquid and expand to slightly more than their original dimensions.

As noted above, one of the important advantages of the present inventionis that the sponges will hold a relatively large amount of the medicatedcosmetic solution. In fact, the amount of aqueous liquid soaked up bythe compressed sponges amounts to over times their weight. Accordingly,when an antiseptic cleaning solution is poured into a suitable containerhaving compressed sponges therein, as shown in FIG. 5, the sponges willimmediately absorb the liquid and return to at least their originalprecompressed volume and shape as shown in FIG. 7. The sponge pads nolonger adhere to each other and are easily separated from one anotherwhen it is desired that one be removed from the jar and used to cleanthe skin.

The basic cellulose sponge material from which the thin sponges of thepresent invention are cut is prepared in conventional manner. In themanufacture of cellulose sponges, the base starting material isgenerally bleached alpha-cellulose, although other cellulosic materialscan also be used. Sheets of alpha-cellulose from wood fibers, such as a12 inch X l2 inch square about three-eighths inch thick, may be used.These sheets are steeped in a concentrated sodium hydroxide solution(usually 50 percent) to produce sodium cellulose.

After the cellulose has been thoroughly soaked at room temperature, thesodium cellulose is removed from the NaOH solution and placed in asealed tank and treated with carbon disulfide to obtain a viscous orangegel known as cellulose xanthate, or viscose. The viscose is pumped intoa blender where fibers, such as hemp, nylon, wood fiber or cotton, inamounts of 1 to 10 percent by weight are added to strengthen the sponge.Then salt crystals, such as Glaubers salt, are added to form the holesof the final sponge. The mixture is then placed in a mold ofa desiredsize, such as inches by 20 inches, and the mold is placed in a dilutebath of sulfuric acid. The dilute acid solution enters the mold throughvarious cutouts" in the mold and breaks down the cellulose xanthate toregenerate the cellulose. Also, the Glaubers salt is dissolved, thusforming the pores in the sponge.

The block of sponge is then washed thoroughly with tap water to removethe carbon disulfide and Glaubers salt. Plasticizer, dissolved in water,if used, is then added by running it through the sponge block. Thesponge block is then dried in an oven.

By the term dry" when used in connection with the cellulose spongematerial that is compressed, we mean that the sponges are dry to thetouch as would be the case when they have established equilibrium withthe ambient atmosphere. Regenerated cellulose sponge material containingup to 12 percent by weight of moisture can be used in preparing the newproducts of the present invention. If the moisture content of thecellulose sponge is too high, the sponges may not stick together asdescribed above.

Although a preferred method of compacting thin cellulose sponges is asdescribed above in which sheets of previously sliced dry regeneratedcellulose sponge material about 20 inches square and one sixty-fourthinch to one-fourth inch in thickness are compressed at 2,00020,000pounds per square inch, the new article of the present invention mayalso be made by preparing bars of regenerated cellulose sponge materialof any desired length and having any desired crosssectionalconfiguration, for example 1% inches by 1% inches, and slicing thesebars in any convenient manner to the desired thickness. A selectednumber of such thinly sliced wafers, for example l0 to 50, are carefullyremoved from the slicing machine and while still in a stacked unit arecompressed with the desired pressures to obtain a unit of about 8 to 20percent of the original thickness of the stacked uncompressed sponges.The density of the compressed sponge unit will depend upon the pressureapplied as well as that of the original sponge. However, as uncompressedsponges have a density of about 2 to 8 grams per cubic centimeter, thecom ressed unit will have a density of about 10 to I00 grams per l0cubic Active Ingredients Percent w/v Salicylic Acid 025 Hexachlorophene0.10 Allantoin 0J0 Carboxycycloimidutc 1.00

These active ingredients are dissolved in 35 to 40 percent alcoholsolutions and a pleasant fragrance as desired is added. In the aboveformula, salicylic acid is a well-known keratolytic agent often used incosmetic and cleaning preparations to promote the healing of acnelesions. Hexachlorophene has been extensively used as an antibacterialagent in acne products, surgical scrubs and toilet soaps. It issubstantive to the skin and nonirritating. Allantoin is widely used intopical preparations to promote healing and stimulate the growth ofhealthy tissue. Carboxycycloimidate is a nonirritating surfactant withexcellent cleaning properties. The alcohol in the product produces asubjective feeling of activity and aids in the cleaning abilities of theproduct.

It will be understood, of course, that the dried compressed sponges ofthe present invention can be saturated with aqueous solutions which willnot of themselves be antiseptic or have cleansing properties. Forexample, the sponges may be saturated solutions having cleansing,astringent, antiseptic as well as medicinal and cosmetic properties ofvarious kinds. The particular nature of the solution is immaterialinsofar as the novel compressed sponges is concerned.

What is claimed is:

1. An article of manufacture comprising a dry coherent unitary bodycomprising a plurality of thin slices of regenerated cellulose spongematerial, the said units being compressed to a thickness of 8 to 20percent of their normal dry thickness and the individual slices thereofadhering to each other while in the dry state.

2. An article of manufacture in accordance with claim 1 in which theindividual slices of regenerated cellulose have a compressed thicknessof 8 to 20 percent of 1/64 inch to A inch.

3. An article of manufacture in accordance with claim 2 in which thecompressed slices have an area of between I and 4 square inches.

4. An article of manufacture in accordance with claim 3 in which thecompressed cellulose sponge unit comprises five to 50 individual thinslices of regenerated cellulose.

5. A method of preparing the article of manufacture of claim 1 whichcomprises subjecting stacks of 10 to 50 sheets of regenerated cellulosesponge material, each sheet having a dry thickness of H64 inch to /1inch to a pressure within the range of 2,000 to 20,000 pounds per squareinch whereby the sheets are compressed to within 8 to 20 percent oftheir original thickness.

6. A method in accordance with claim 5 in which the compressed sheetsare cut into units having an area of l to 4 square inches.

2. An article of manufacture in accordance with claim 1 in which theindividual slices of regenerated cellulose have a compressed thicknessof 8 to 20 percent of 1/64 inch to 1/4 inch.
 3. An article ofmanufacture in accordance with claim 2 in which the compressed sliceshave an area of between 1 and 4 square inches.
 4. An article ofmanufacture in accordance with claim 3 in which the compressed cellulosesponge unit comprises five to 50 individual thin slices of regeneratedcellulose.
 5. A method of preparing the article of manufacture of claim1 which comprises subjecting stacks of 10 to 50 sheets of regeneratedcellulose sponge material, each sheet having a dry thickness of 1/64inch to 1/4 inch to a pressure within the range of 2,000 to 20,000pounds per square inch whereby the sheets are compressed to within 8 to20 percent of their original thickness.
 6. A method in accordance withclaim 5 in which the compressed sheets are cut into units having an areaof 1 to 4 square inches.